Improvement in the manufacture of oakum



UNITED STATES PATENT OEEIoE. I

THOMAS H. DUNHAM, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN THE MANUFACTURE OF OAKUM.

Specification forming part of Letters Patent N0. 220,358, dated October7, 1879; application filed February 14, 1879.

To all whom it may concern:

Be it known that I, THOMAS H. DUNHAM, of Boston, county of Suffolk, andState of Massachusetts, have invented certain Improvements in theManufacture of Oakum, of which the following is a full, clear, concise,and exact description.

Heretofore the substance called oakum, which is ordinarily tarred flaxor hemp, has generally been made either from tarred rope or inaccordance with my Patent No. 146,438, granted January 13., 1874; andthis oakum made from tarred flax or hemp was the only calking materialused, to my knowledge, until within a few years, atwhich time cotto'nuntarred was introduced, and has since been used to a considerableextent, as a calking material for light vessels and decks; but thiscalking is not adapted for general use as a substitute for oakum, andhas not been so used, but only in seams not exposed to any great strain.This untarred cotton is objectionable, because the tendency is to absorbmoisture, which soon rots the fiber and renders it useless, and alsobecause of a tendency, when dry, to work out of the seams, and in boththese respects it is much inferior to the oakum usu ally used.

I have invented a new article of manufacture, the article being atarred-cotton oakum, ready for use without the preliminary handspinningrequisite with the common oakum.

To manufacture my new article I first reduce the dry cotton to the formof a longloose fibrous and puffy strand by machinery too well known toneed anydeseription, the strand being also well known in the manufactureof cotton under several names, being most generally called a roving, butsometimes a sliver. This roving is uniform, or very nearly so,throughout its length, and usually about an inch in diameter, althoughIvary its diameter according to the size of the oakum required, as willbe clear to all calkers without further description. I then lay thissliver onto an endless apron of strong cloth, which passes into and outof a tank and between a pair of squeezing-rollers. The tank being filledwith boiling tar, or tar dissolved in naph tha, (or otherwise madesufficiently fluid,) the motion of the apron will carry the rovingthrough the tar and between the rolls, which express the superfluoustar, the roving after leaving the feed-roll being ready for use asoakum, the strand of fiber having been reduced to the desired sizebefore it is tarred, and constituting a new article-tarred-cotton oakum.

Two or more strands may be pressed through the tank and rollers on awide apron as well as one strand, it being found that the strands alwayskeep separate and distinct.

My new article differs from all other oakum known to me in that thefiber of cotton is much more uniform, both as to length and firmness ofthe fibers, than of hemp or flax, and also much finer than any fiberheretofore found in oakum. Its strength is also very much greater, andit will, when tarred, make avery fine compact wedge, which clings withgreat force to the seam, will not rotnor become displaced, and whichcompletely fills the space between the planks, especially the apex ofthe wedge, all oakum when in place being wedgeshaped, but the ordinaryoakum,loy reason of the coarseness of its fibers, having a blunt anduneven apex, instead of the fine sharp apex produced with my newtarredcotton oakum.

When the tar is kept at a boil it is, of course, very desirable to keepthe roving always upon the feed-apron, and to insure this I use anuptinuous.

What I claim as my invention is- As a new article of manufacture, thetarredcotton oakum above described, composed of a roving of cottonsaturated with tar.

THOMAS H. DUNHAM.

Witnesses:

G. H. SLADE, GEORGE O. G. COALE.

